1. Technical Field
The present invention relates to a mouth opening instrument used, for example, in dental treatment.
2. Description of the Related Art
A patient's mouth is required to be kept open during dental treatment. Therefore, a mouth opening instrument that is set between the upper and lower teeth of the patient, such as that described in JP-A-2007-282698, is proposed.
When the mouth opening instrument described in JP-A-2007-282698 is used, the patient's mouth is kept open at all times regardless of the circumstances during the dental treatment. Therefore, the patient experiences distress, such as from not being able to swallow saliva. Thus, a mouth opening instrument is desired that can be appropriately controlled based on the circumstances during dental treatment.